how do you simplify this equation?

This is a simple expansion equation. Technically speaking, it is already simplified, but you can expand the equation by multiplying the 8x to each item inside the parenthesis.

8x*x^2=8x^3
8x*3=24x

Therefore, the expanded equation looks like this:
8x^3+24x.

9x squared + 3

8 x ³ + 24 x

8x(x^2+3)
you simply distribute the 8x to both numbers in the bracket
= 8x^3+24x

8x*x^2 + 8x*3
8x^3 + 24x

It's already simplified. Another answerer shows how to expand it out. If you really want to get clever, you can add and subtract anything you want, multiply and then divide by the inverse, etc. for example it is also equal to: 8x(x^2+3)-3.14159+3.14159+29/33-29/33+x^9-x9

It's already simplified. To expand:

8x^3 + 24x

8x(x^2 + 3)
= 8x*x^2 + 8x*3
= 8x^3 + 24x